Packaging for optical component

ABSTRACT

An optical package ( 40 ) suitable for use in a moist environment, the assembly comprising: (a) an optical component ( 41 ); (b) a housing ( 42 ) defining at least a main compartment containing the optic al component ( 41 ) and at least one access route along which ambient moisture must travel to reach the optical component ( 41 ); and (c) a desiccant material ( 50 ) disposed along the access route such that moisture entering the housing ( 42 ) contacts the desiccant material ( 50 ) before reaching the optical component ( 41 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application based onInternational Application No. PCT/US02/01688, filed Jan. 29, 2002, whichclaims priority benefit under 35 U.S.C. § 119(e) to U.S. ProvisionalApplication No. 60/262,307, filed Jan. 29, 2001, the disclosures ofwhich are incorporated herein by reference.

FIELD OF INVENTION

This invention relates generally to optical component packages and, moreparticularly, to optical component packages that are suitable for moistenvironments.

BACKGROUND OF INVENTION

Recent trends show a dramatic increase in the applications of opticalfiber and optical components. These new applications have placed demandsnot only on the optical components and their performance, but also onthe packaging of these components. Today's optical packages need to berobust and suitable for a wide range of environments. Of particularinterest herein are optical packages for use in high-moistureapplications such as those found outdoors, in industrial plants andmachinery rooms, underground or underwater.

One approach for packaging an optical component, such as a channelsplitter, involves placing the component in a tube and then sealing thetube on each end with an end cap. More specifically, with reference toFIG. 1, this package 10 is assembled by applying adhesive to theperimeter of the end cap 14 (typically while rotating using ahand-operated fixture) and to the orifice in the end cap through whichthe fiber 15 (or wire) passes. As used herein, the term “adhesive”refers broadly to both adhesives and sealants. Next, the end cap ispushed into the tube 12. Typically, both end caps are pushed into placesimultaneously. The adhesive 13 is then cured while the tube is layingon its side.

This packaging configuration is advantageous in that the end cap 14 isexposed to ambient conditions rather than the adhesive 13. Minimizingthe adhesives' exposure to the environment is important since it istypically through the adhesive that moisture enters the housing anddamages the optical component.

Despite the advantageous of this approach, the applicants haveidentified a number of problems with it. First, as shown in FIG. 1,since the epoxy 13 is typically cured while the tube 12 is on its side,an asymmetric distribution of adhesive results. This is especiallyproblematic since it is difficult to control the application of adhesivearound the perimeter of the end cap 14 in the first place, thus, oftentoo much adhesive is applied. If too much adhesive is applied, it mayinterfere with the delicate internal optical component 11, especiallygiven the asymmetric distribution of adhesive. Furthermore, the volumeof adhesive may be so large that it imposes expansion/contractionstresses on the packaging during thermal cycling. The uncontrolleddistribution of adhesive also increases the possibility of leaving voidsin the seal. Aside from problems controlling the adhesive, the adhesiveitself may hold moisture which can escape into the housing afterpackaging and thereby cause the humidity level inside the housing torise, perhaps to the detriment of the optical component.

Given these difficulties, the applicants have developed an approach forcontrolling the application of adhesive to the optical package 20 bypartitioning the tube 22, preferably with a washer 24, to separate theadhesive 23 from the optical component 21 as shown in FIG. 2. Inmanufacturing an optical package 20 according to this approach, the tube22 is held vertically and a washer 24 is placed against a ridge 25 onthe inside of the tube 22. Next, the adhesive 23 is applied to thepartition formed by the washer 24 and tube 22, and cured. The assembly20 is then flipped so that the other end is up, and the procedure isrepeated.

This approach offers a number of advantages over the prior art approach.First, the sealant partition confines the adhesive and prevents it fromflowing into or otherwise interfering with the optical component.Furthermore, since the adhesive is applied to the washer when the tubeis vertical and unobstructed with an end cap, it is easy to control theplacement and volume of the adhesive. Consequently, the adhesive can bedirected precisely to fill around the fiber, minimizing the risk ofleaving voids which might transmit moisture. Furthermore, unlike theprior art approach, no skill is required to fill the adhesive into theend cap region and minimal fixturing is required.

The partition also facilitates “pre-sealing.” In pre-sealing, the gapsaround the partition are filled with a quick-cure adhesive which curesbefore it has a chance to flow into the main compartment housing theoptical component and potentially interfere with the optical component.Once the gaps are filled, more liberal quantities of an additionaladhesive may be applied to properly seal the housing. The cure time anddispersion of the additional adhesive are not critical since there is norisk of it entering the main compartment and interfering with theoptical component. Thus, the additional adhesive may be selected basedon more desirable properties such as resistance to water or otherambient conditions.

Unfortunately, this approach leaves a great deal of adhesive exposed tothe environment. Exposing adhesives to a moist environment is generallyundesirable because moisture tends to permeate the adhesive over timeand eventually enter the main compartment where it can damage thesensitive optical component. Furthermore, it is likely that the adhesivewill undergo some degradation due to either ambient moisture or otherambient condition (e.g., ultraviolet radiation, abrasion, causticsubstances, etc.).

In light of this shortcoming, the applicants have developed yet anotherapproach which eliminates the adhesive's exposure to the environment.More specifically, with respect to FIG. 3, rather than just partitioningthe adhesive from the optical component, the housing 31 defines aseparate sealant compartment 33 which is isolated from both the opticalcomponent 31 and the environment. In manufacturing this package, a tube32 is held vertically and a washer 38 is placed against a ridge 39 onthe inside of the tube 32. An ultraviolet (UV)-curing adhesive 34 isused to seal the edge of the washer and around the fiber 36. Next, anadditional adhesive 37 is applied on top of the washer and around theend cap 35, and the end cap 35 is put in place and cured. It is expectedthat adhesive flows out of the end cap around its perimeter and alongthe fiber. The UV adhesive, however, keeps the adhesive from flowinginto the compartment containing the optical component 31. Note that theend cap 35 should have the correct fit around its perimeter and throughthe fiber hole such that adhesive will flow through. Adhesive in theselocations provides a longer path through which moisture must diffuse.Once the adhesive is cured, the device is then flipped so that the otherend is presented up, and the procedure is repeated.

Pre-sealing the washer offers a number of advantages aside from keepingthe end cap adhesive from entering the chamber as mentioned above.Specifically, if the washer is not pre-sealed, it is necessary to use anadhesive of a certain viscosity which is thick enough not to flowthrough the hole in the washer, but which is thin enough to flow aroundall components that are to be bonded. The choice of adhesive iscomplicated by the fact that adhesives tend to flow more easily whenthey are heated which is often required for curing epoxies. Furthermore,when the tube is sealed, air is trapped inside the tube. If the tube isheated or cooled before the end cap adhesive has cured, the pressureinside the tube changes, forcing air out of or into the tube through theuncured adhesive. This can result in a permanent leak path once the endcap adhesive has cured. Pre-sealing avoids these complications.Pre-sealing also protects the internal components from any vapor whichmight be released during the cure of the end cap adhesive. The featuresof pre-sealing allow a wider variety of adhesives to be used for thefinal end cap sealing.

The advent of the sealant compartment offers a number of significantadvantages. In addition to the advantages of the partition approachmentioned above, the sealant compartment approach also minimizes thearea of adhesive that is exposed to the environment. As mentioned abovethis is important since moisture typically passes through adhesives overtime and tends to degrade the adhesive.

Despite these advantages, however, under extreme moisture conditions,the risk remains that the adhesive barrier will be breached and moisturewill enter the tube. Therefore, if the optical component contained inthe tube is particularly susceptible to moisture and the environment isparticularly moist, this approach may be insufficient.

Therefore, a need remains for a packaging approach that provides a highlevel of moisture protection for moisture-sensitive optical components,even at extreme conditions. The present invention fulfills this needamong others.

SUMMARY OF INVENTION

The present invention provides for an optical package which uses adesiccant to absorb or otherwise nullify any moisture that enters thehousing of the package. Thus, rather than attempting to design andmanufacture a perfectly hermetically-sealed package, which becomesexponentially more difficult to achieve as the tolerance for moisturedecreases, the package of the present invention needs to be onlyreasonably moisture-proof given its relatively high tolerance formoisture. This relaxes the manufacture and design needs of the packageof the present invention and facilitates the use of relativelyinexpensive materials and conventional manufacturing techniques.Therefore, the present invention exploits the observation that it is fareasier to remove any moisture that might pass through the housing of anoptical package, than it is to prevent the moisture from entering in thefirst place.

One aspect of the invention is an optical package comprising adesiccant. In a preferred embodiment, the package comprises: (a) anoptical component; (b) a housing defining at least main compartmentcontaining the optical component; and (c) a desiccant material disposedin the vicinity of the optical component to remove a substantial portionof any moisture entering the housing. Preferably, the housing comprisesat least one access route, along which ambient moisture must travel toreach the optical component. In such a configuration, the desiccant isdisposed along the access route such that moisture entering the housingcontacts the desiccant material before reaching the optical component

Another aspect of the invention is a process of manufacturing theoptical package by partitioning the desiccant and adhesive. In apreferred embodiment, the process comprises: (a) positioning an opticalcomponent in a main compartment of a housing; (b) placing a desiccant inthe housing such that ambient moisture that enters the housing contactsthe desiccant before reaching the optical component; (c) pre-sealing thehousing to establish a partition to prevent an adhesive used for sealingthe housing from entering the main compartment; and (d) sealing thehousing to prevent substantially moisture from entering the housing.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates the applicants' concern with the prior art method ofpackaging optical components;

FIG. 2 shows an improved approach for packaging optical components inwhich the adhesive is partitioned from the optical component;

FIG. 3 shows another improved packaging approach which utilizes aseparate sealant compartment for isolating the adhesive from both theambient environment and the optical component; and

FIG. 4 depicts the packaging approach of the present invention in whicha desiccant is used.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring to FIG. 4, a preferred embodiment of the packaging system ofthe present invention is shown. The packaging system 40 is suitable forparticularly high humidity or moist conditions. Such conditions can befound in a number of environments such as, for example, outdoors, insideindustrial plants and machinery rooms, underground or underwater.

The optical package 40 comprising an optical component 41, a housing 42defining at least a main compartment 51 containing the optical component41 and at least one access route 52 from the environment to the maincompartment 51. The optical package also comprises a desiccant material50 disposed along the access route 52 such that ambient moistureentering the housing must pass by the desiccant material 40 to accessthe optical component 41. The various components of the optical packageare discussed below in greater detail.

At the heart of the optical package is the optical component 41. As usedherein, the term “optical component” is used broadly to coverpurely-optical or optoelectric components used in both passive andactive devices. The term “passive devices,” as used herein, refers toany optical or optoelectric device that manipulates an optical signalbut which does not impart energy into the system. Examples of passivedevices include add/drop filters, silica planar waves guides, arrayedwave guide gratings (AWGs), splitters/couplers, and attenuators. As usedherein, the term “active device” refers to any optical or optoelectricdevice that either converts signals between optical and electricaldomains or imparts energy into an optical system. Examples of activedevices include lasers, photodiodes, and optical amplifiers. The opticalcomponent may be part of a larger assembly or it may comprisesubcomponents.

Optical components tend to be susceptible to environmental conditionssuch as humidity and dust. Those optical components having exposedoptical paths are especially sensitive to moisture and dust sincemoisture droplets and dust can interfere with the optical path. Forexample, a dust particle is approximately the same size as the core of asingle mode fiber and, thus, can totally obscure the fiber and ruin thedevice's performance. Due to the sensitive nature of optical components,it is important to package them to minimize the external threats such asmoisture and dust. To this end, the packaging approach of the presentinvention employs a housing 42 which contains the optical component 41.

The housing 42 can be formed of a variety of materials, however, it isgenerally preferred that these materials be rigid, water resistant, andreadily formable. Additionally, it may be preferable, in somecircumstances, to employ an energy-absorbing material in the housing toafford a certain measure of shock resistance. Suitable materials includefor example, plastics, metal, and rubbers and combinations thereof.Preferably, the housing is made of a metal due to its ready availabilityand durable nature. Examples of preferred metals include, for example,stainless steel and aluminum.

The shape and configuration of the housing can vary depending upon theapplication and the invention is, by no means, restricted to anyparticular shape. The housing must define a main compartment 51 forcontaining the optical component and preferably an access route into themain compartment for placing the optical component therein. Although theaccess route initially provides passage into the main compartment, itshould be understood that the access route is eventually sealed from theenvironment, preferably in a permanent fashion. Therefore, as usedherein, the term “access route” refers to the initial state of thehousing and that the access route is sealed in the completed package.One should also appreciate that even though the access route is sealed,it nevertheless represents a “weak link” in the housing through whichmoisture tends to be more likely to enter then through any other pointof the housing.

It is generally preferable to minimize access routes and joints in thehousing, thereby minimizing the potential sites through which moistureand/or dust can enter the housing and potentially damage the opticalcomponent. Accordingly, shapes such as elongated tubes or cans which areintegrally formed (seamless) are preferable. For example, as shown inFIG. 4, the housing 42 is an elongated tube having two ends. It shouldbe understood that FIG. 4 only depicts one end and that a similarconfiguration can be found at the other end of the elongated tube.Although seamless housing structures are preferred, it should beunderstood that a housing made of various components which are welded orotherwise combined is within the scope of the invention.

The housing of the present invention is partitioned to define differentcompartments which serve different purposes. As shown in FIG. 4, thepackage has a main compartment 51, a desiccant compartment 53 adjacentto the main compartment 51, and a sealant compartment 43 between thedesiccant compartment 53 and the environment. Each compartment in thisconfiguration serves a different purpose.

The sealant compartment 43 contains the adhesive which serves to sealthe housing from the environment to substantially prevent the moisturefrom entering the housing. The term “substantially” as used in thiscontext is intended to convey that most of ambient moisture is preventedfrom entering the housing but not necessarily all. It is not critical tothe present invention that the housing be sealed to prevent a certainamount of moisture from entering the housing. However, since thedesiccant tends to be a consumable resource, its life cycle is likely tobe shortened as the amount of moisture that is permitted to enter thehousing increases.

The sealant compartment 43 (as described above in the backgroundsection) enables one to seal the package without the risk of potentiallycontaminating or otherwise interfering with the optical component withthe adhesive. More specifically, the partition 48, as shown in FIG. 4,may be set in place and then “pre-sealed” with a quick-cure adhesive,such as a UV-curable epoxy. The quick-cure adhesive may be applied toany gaps in the partition such as, for example, the perimeter 44 a ofthe partition 48 or the hole 44 b through which a fiber 46 (or wire)passes through the partition 48. By precisely applying the adhesive tothese areas and quickly curing it, the risk of the adhesive flowing intothe main compartment and potentially damaging the optical component isminimized considerably. Additionally, once the quick-cure adhesive is inplace, a barrier to the main compartment 51 is established and it isthen possible to apply a more liberal quantity of additional adhesive tosecure the end cap 45 in place.

The types of adhesives used can vary and are within the purview of oneskilled in the art. For reasons as mentioned above, however, it isgenerally preferred that, when “pre-sealing” the housing, a quick-cureadhesive be used. Suitable quick-cure adhesives are known in the art andinclude, for example, UV-activated epoxies, epoxies with fast-actingcatalysts, or adhesives which set immediately upon exposure to a certainamount of energy which is readily deliverable in situ. The additionaladhesive which is applied to secure the end cap 45 or similar device inplace need not be selected based on its cure-rate characteristics sinceit may be allowed to flow during curing. Rather, the additional adhesiveshould be selected based on properties more germane to itspurpose-namely, to seal the housing and resist the penetration of dustand moisture. To this end, an adhesive is preferred which has strongadhesive properties to hold the end cap or similar structure and whichis resistant to water penetration and degradation. Again, such adhesivesare known in the art, although epoxies, polyurethanes, and acrylates arepreferred, and epoxies are more preferred. Due to pre-sealing, the rateat which the additional adhesive cures is not critical, although forcommercial purposes it is preferable that its cure rate be quick enoughto achieve reasonable manufacturing throughput.

Referring now the desiccant compartment 53, its function is to hold thedesiccant 50 along the access route 52 such that ambient moisture mustpass the desiccant to reach the optical component. Additionally, thedesiccant compartment also serves to contain the desiccant and separateit from the optical component. This later feature may be critical if thedesiccant is particularly dusty (as desiccates tend to be) and if theoptical component is particularly susceptible to dust. As mentionedabove, optical components which tend to be susceptible to dust are thosewhich have an exposed optical path. It should be understood, however,that if the desiccant used is not particularly dusty or if the opticalcomponent is not susceptible to dust, then there need not be a sealedpartition between the desiccant and the main compartment. In otherwords, the desiccant could be situated in the main compartment so as toremove substantially any moisture that enters the housing. Regardless ofwhether the desiccant is in its own compartment, it is preferable toposition the desiccant such that any ambient moisture entering thehousing contacts the desiccant before reaching the optical component.

The partitions used to define the sealant, desiccant and maincompartments may assume a variety of forms. For example, as shown inFIG. 4, the partition 48 that separates the sealant compartment from thedesiccant compartment is a circular washer that seats on a ledge 49formed by the desiccant 53. The partition 55 that separates the sealantcompartment 43 from the main compartment 51 is also a washer that seatson a ridge 54 which is machined or otherwise formed in the interiorsurface of the elongated tube 42. Each washer has an aperture (notshown) approximately in its middle to allow passage of the fiber 46. Asmentioned above, it is generally preferred that the perimeter around thewashers and the aperture be sealed with an adhesive. Although thisapproach for partitioning is preferred from the standpoint ofsimplicity, availability of components, and ease of manufacture, otherapproaches are within the scope of the present invention. For example,the partitions may be tack welded in place or the partitions mayactually define separate compartments of the housing which are joined(e.g., welded) together to form the completed housing.

To seal the housing closed, an end cap 52 is preferred. As mentionedabove, an end cap is preferred since it leaves very little of theadhesive exposed to the environment. It should be understood, however,that other mechanisms may be used to seal the housing such as, forexample, a screw top, a lid which is welded or otherwise fastened inplace, or a stopper which perhaps is elastically deformable to presentan urging force against the housing when in place to effect a frictionfit with the housing.

The desiccant used may be any drying agent, including either a chemicaldesiccant which acts by absorption, for example, by reacting with water(e.g., phosphorous pentoxide) or a physical desiccant which acts byadsorption (e.g., a silica gel). Suitable desiccants include forexample, P₂O₅, Mg(ClO₄)₂, KOH, H₂SO₄, NaOH, CaO, CaCl₂, ZnCl₂, CuSO₄andzeolites, such as Na₂O. 2Al₂O₃.5SiO₂ and CaO.2Al₂O₃.5SiO₂. Preferably,the desiccant is a zeolite. Many desiccants tend to be somewhat brittleand produce dust if subject to shock or vibration. As mentioned above,dust is not tolerable for certain optical components. To avoid therelease of dust and thus the need for a separate desiccant compartment,it may be preferred to embed/disperse/suspended the desiccant in aplastic or gel or otherwise covered it in plastic. These desiccant formstend to be more resilient to the formation of dust and, as mentionedabove, the housing may be simplified if such desiccants areused-specifically, the partition separating the desiccant from theoptical component may be eliminated.

The shape of the desiccant material may vary within the scope of theinvention, although consideration should be given to its exposed surfacearea since the absorption/adsorption process tends to occur only on thesurface. Examples of suitable forms of desiccant include, for example, apacked bed of pellets (or other particularized form of desiccant) or anaggregate of desiccant such as a solid disk. Preferably, theconfiguration of the desiccant allows for its placement in the housingwithout the need to thread the desiccant down the length of a fiber orwire. For example, in the case of a packed bed, the pellets may simplybe poured around the fiber or wire. In the case of a desiccantaggregate, slotted disks or discrete disk segments may be placed aroundthe fiber or wire. In a preferred embodiment, the desiccant is aC-shaped slotted disk.

The optical package of the present invention as described above lendsitself to a readily-commercializable manufacturing process. In thepreferred embodiment, the process comprises holding the elongated tubevertically and placing the partition 55, which is preferably a washer,against a ridge 54 on the inside surface of the tube. Next, a UV-curingadhesive is used to provide a seal 56 around the perimeter of thepartition 55 and a seal (not shown) around the fiber 46. This partitiondefines one end of the desiccant compartment 53. Next, the desiccant 50is placed upon the partition 55 and a second partition 48, which is alsopreferably a washer, is put in place against a support, which in thisembodiment is part of the desiccant structure. Again, a UV-curingadhesive is used to provide a seal 44 a around the perimeter of thesecond partition 48 and a seal 44 b around the fiber 46. This secondpartition serves to further define the desiccant compartment 53 as wellas to establish one side of the sealant compartment 43. At this point,adhesive is applied liberally to the top of the second partition 48 andaround the end cap 45. The end cap 45 is put in place while allowing theadhesive to flow out of the end cap's perimeter and its fiber hole. Asmentioned above, the UV-curable adhesive prevents adhesives from flowingpast the partition 48 and into either the main compartment or thedesiccant compartment. At this point, the adhesive is cured and thedevice is flipped so the procedure may be repeated to the other end.

The compartmentalized configuration of the optical package of thepresent invention lends itself to a high degree of reliability inmanufacturing and uses assembly techniques which are readilycommercializable in that they can be scaled up and automated. Basically,the packaging begins with the optical component and works its way outone compartment at a time, one end at a time. The use of pre-sealing asmentioned above controls the flow of adhesive and minimizes risk ofcontaminating the optical component. Furthermore, as mentioned above,since the optical package of the present invention relies on thedesiccant interacting with any moisture that may penetrate the housing,the package need not be over engineered to prevent moisture fromentering. In other words, rather than designing and constructing aperfectly hermetically sealed package, which becomes exponentially moredifficult as the tolerance for moisture decreases, the packaging of thepresent invention uses relatively simple and known constructiontechniques with relatively simple and known components to manufacture areasonably water-tight package and relies on the desiccant to nullifyany moisture that may penetrate the housing.

1. An optical package suitable for use in a moist environment, saidassembly comprising: an optical component; a housing defining at least amain compartment containing said optical component, and an access routealong which ambient moisture must travel to reach said main compartment;and a desiccant material disposed in the housing to substantially removeany moisture entering said housing, said desiccant being disposed alongsaid access route such that moisture entering said housing contacts saiddesiccant material before reaching said main compartment.
 2. The opticalpackage of claim 1 wherein said housing is elongated with two ends, saidaccess route extending from at least one of said ends to said maincompartment.
 3. The optical package of claim 1, wherein said accessroute is sealed substantially from ambient moisture by an adhesive andsaid housing defines a partition between the adhesive and the opticalcomponent.
 4. The optical package of claim 1, wherein said housingcomprises a sealant compartment along said access route, said sealantcompartment containing said adhesive.
 5. The optical package of claim 4,wherein said desiccant is between said main compartment and said sealantcompartment.
 6. The optical package of claim 5, wherein said desiccantis contained in a desiccant compartment which is partitioned from saidmain chamber.
 7. The optical package of claim 5, wherein said desiccantis not partitioned from said main compartment.
 8. The optical package ofclaim 7, wherein said desiccant is dust-resistant.
 9. The opticalpackage of claim 7, wherein said optical component does not have anexposed optical path.
 10. The optical package of claim 1, wherein saiddesiccant is at least one of P₂O₅, Mg(ClO₄)₂, KOH, H₂SO₄, NaOH, CaO,CaCL₂, ZnCl₂, CuSO₄, or zeolites.
 11. The optical package of claim 10,wherein said desiccant is zeolite.
 12. The optical package of claim 1,wherein said optical component is at least one of add/drop filters,silica planar waves guides, arrayed wave guide gratings (AWGs),splitters/couplers, attenuators, lasers, photodiodes, detectors oroptical amplifiers.
 13. An optical component package comprising: anoptical component; a housing having at least a main compartmentcontaining said optical component, a sealant compartment through whichambient moisture must pass to reach said optical component, and adesiccant compartment disposed between said sealant compartment and saidmain compartment, an adhesive contained within said sealant compartment,said adhesive substantially preventing ambient moisture from enteringsaid housing; and a desiccant contained within said desiccantcompartment such that moisture entering said housing contacts saiddesiccant before reaching said optical component.
 14. The opticalpackage of claim 13, wherein said housing comprises an elongated membercontaining a number of partitions, a first partition separates said maincompartment from said desiccant compartment, a second partitionseparates said desiccant compartment from said sealant compartment andwherein said elongated member has an end cap on one end, thus, said maincompartment is on one said of said first partition, said desiccantcompartment is between said first and second partitions, and saidsealant compartment is between said second partition and said end cap.15. The optical package of claim 14, wherein said elongated member is atube and said first and second partitions are washers in said tube. 16.The optical package of claim 15, wherein the interior surface of saidtube has ridges upon which at least one washer abuts.
 17. A process formanufacturing an optical package, said process comprising: positioningan optical component in a main compartment of a housing; disposing adesiccant in said housing such that ambient moisture entering saidhousing contacts said desiccant before reaching said optical component;pre-sealing said housing in which a partition is establish to prevent anadhesive used for sealing said housing from entering said maincompartment; and sealing said housing with said adhesive to preventsubstantially moisture from entering said housing.
 18. The process ofclaim 17, further comprising establishing a barrier between said maincompartment and said desiccant such that dust from said desiccant cannotenter said main compartment.
 19. The process of claim 17, whereinpre-sealing comprises applying a quick-cure adhesive to gaps to preventsaid adhesive from passing.
 20. The process of claim 19, wherein saidadhesive has a lower cure rate than said quick-cure adhesive.